Yarn tension device



March'B, 1953 F. J.' KENT YARN TENSION DEVICE 5 sheets-sheet 1 Filed June 11, 1948 INVENTOR 36 65 .Egderick J Kenf 6% mam March 3, 1953 F. J. KENT YARN TENSION DEVICE 5 Sheets-Sheet 2 Filed June 11, 1948 INVENTOR Egierick .IKenZ- Ano lfz March 3, 1953 F. J. KENT 2,630,281

YARN TENSION DEVICE Filed June 11, 1948 s Sheets-Sheet 5 INYENTOR ffiderzc/c J Kent @0111 ATTORN Patented Mar. 3, 1953 UNITED STATES PATENT OFFICE YARN TENSION DEVICE Frederick J. Kent, Fair Lawn, N. J.

Application June 11, 1948, Serial No. 32,453

11 Claims. 1

This invention relates to tension means for yarn and thread or the like, and particularly to tension devices which are adapted to be used in warping yarns or other strands where, for example, several hundred individual strands are simultaneously delivered to the warper.

An object of this invention is to provide for maintaining uniform tension on strands, such as, yarn, thread or the like, even though there are wide variations in such factors as the condition of the strand, the atmospheric conditions, the conditions at the source of the strand, and the air resistance which is apt to vary due to ballooning of the strand. A further object is to provide for automatic and instantaneous compensation for tension variations. A still further object is to provide for the above while avoiding objectionable features of the prior art, such as, the pinching or scraping of the strand when it is pressed between two opposing surfaces, and the tendency for objectionable oscillation of the strand and tension-devices during use.

Another object is to provide an improved snubbing mechanism whereby the snubbing efiect may be varied to obtain an infinitely variable and accurately controlled tension within the range of the device, such for example as of the order of between three and twelve grams. Another object is to provide an improved primary tension device which will subject the strand to an ac- 3 curately controlled tension resulting from producing resistance to movement. Another object is to provide an improved snubbing mechanism such as that referred to above, together with a primary tension device which will maintain accurate control upon the snubbing action.

A further object is to provide for the above with mechanism which is light in weight, sturdy and simple in construction, inexpensive to manufacture and maintain, and which is efficient and dependable in use. These and other objects will be in part obvious and in part pointed out below.

The invention accordingly consists in the features of construction, combinations of elements, arrangements of parts and in the several steps and relation and order of each of the same to one or more of the others, all as will be illustratively described herein, and the scope of the application of which will be indicated in the following claims.

In the drawings in which is shown one illus trative embodiment of my invention;

Fi ure 1 is an enlar t p plan view of a yarn tension device;

Figures 2 and 3 are enlarged sectional views on the lines 2-2 and 3-3 of Figure 1;

. Figure 4 is a fragmentary bottom plan view Figure 6 is a view similar to Figure 1 showing.

the mode of threading the device;

Figure 7 is an enlarged schematic view demonstrating the operation of the device; and

Figure 8 is a view similar to Figure 5 but on a smaller scale and showing another condition of operation.

A number of synthetic fibers such as nylon have been recently developed with the tendency to reduce the size of the strands to finer denier counts, so as to produce more delicate fabrics which are soft and have superior draping qualities. The reduction of the strand size has been accomplished with a reduction in the diameter of the filaments, and these finer filaments are very delicate and are easily damaged during the weaving or knitting process. In order to protect the filaments the yarn is treated with a sizing compound which is subsequently removed from the finished fabric, but even with this additional protection the fibers are difiicult to handle and they often break.

When preparing the warp either for weavin or knitting, the arn-is delivered to the warper from a suitable creel with 600 or more strands or running ends. To produce a perfect warp it is essential that the tension on all of the strands be substantially the same and that this tension not vary during the warping operation. Fine nylon yarns have considerable elasticity and the tension should be less than the elastic stretch point of the yarn which is of the order of four to five grams. The tensioning mechanism heretofore. available is not capable of providing a consistent and uniform low tension of this order.

With certain of the prior tensioning devices the yarn is subjected to pressure between two surfaces so that some of the sizing rubs oil, and this tends to build up on the surfaces of the device su'fficiently to hold the surfaces apart; the result is that the tension is reduced materially, or it is even stopped completely. Also, with delicate yarn, even slight pressure by the surfaces tends to flatten the yarn and push the twist of the yarn back toward the supply; and, this action is apt to continue until sufficient twist is accumulated to cause snarling of the yarn, and interruption of the yarn delivery.

With elastic yarns, such as nylon, there is a tendency for certain of the prior tension devices to set up harmonic oscillations of the yarn. Such oscillation occurs when such factors as, the speed of yarn delivery, the tension and elasticity of the yarn, and the ballooning of the yarn ofi the supply cone, all combine to react harmonically w th respect to one or several elements of the tens on device. These oscillations cause rapid repetition, of alternate low and high tensioning of the yarn which causes faulty warping and may be even sufficient to break the yarn. It is among the objects of the present invention to provide a tensioning device which avoids these and other difficulties which have been encountered with prior devices.

In accordance with the present invention the yarn or other strand passes a snubbing device where it is subiected to a snubbing action which varies automatically to maintain substantially constant tension throughout a wide range of operating conditions.

In the illustrative embodiment of the invention, the. incoming strand may be drawn from a supply cone under little or no tension, and in order to get a continuous snubbing action an initial tension device is provided which imposes an initial tension to the incoming strand so that the strand passing to the snu bing device will always be under some tension. The total tension on the outgoing strand passing from the tension device is the sum total of the initial ten ion on the incoming yarn, the tension produced by the primary tension device. and the tension produced by the snubbing action. The arran ement is such that the snubbing action is varied instantaneously and automatically to compensate for variations in the tension of the strand pa sing to the snubbing device. The snuhbing action is varied by chan ing the angle of snubhing cont ct bet een the yarn and the snubbing device. The snubbing device inclu es a num er of snu bing posts which are mounted around the periphery of a rotatable disc structure. A s ring tends to rotate the di c structure to ard one extreme of its limited rotarv movement. and t e arran ement is such that an increase i tens on of the strand tends to r tate this disc Structure a ainst the action of th s s ring: such rotat n of the disc structure reduc s the a le of snuhbin c ntact an decreases the snu bin action with the result that the total tension tends to remain constant.

Referrin nart cu arl" to F ure in th d a in s. a substant l triangular base frame 2 is adapted to be ri idlv attached to a m unting bar 4 b a s t s re 6 carr ed bv a ubstatiquv semi-cvlindrinal flan e 1. F m 2 h s m unted thereon a prim rv tension dev ce 8 and a sec nd tension or snu bing de ice H1. The incoming strand or yarn is dra n from a yarn su nlv cone or spool (not shown) through a porcelain sleeve l2. havin a ri id fi er disc '4 m unt d thereon. to the primarv tension device 8 and then around the snu bing device l0, and the outgoi g strand passes through a porcelain sleeve to the warper.

As sho n best in Fi ure 3. the pr mar tension device 8 has a central post '8 wh ch is rigidly held bv screw in a poc"et l9 in frame 2. Surrounding the post is a fixed c lindrical porcelain bushing 22, which is cemented in a rece s in the frame. Loosely mounted on post 8 is a movable cylindrical porcelain bushing 24 h ch is smaller than bushing 22 and is adapted to fit therein and telescope therewith with an annular space 2| around the outside of bushing 24. At the bottom of space 2| there are three openings 23 (see also Figure 4) in the bottom of frame 2 through which dirt may fall from this space, and pocket [9 is connected to the main body of the frame by three webs. Bushing 24 is limited in its upward movement (Figure 1) by a screw 25 which is threaded in a hole in the top of the post with its head overlying the edge of the post to provide an abutment for the bushing.

At the level of the bushings, post l8 has a somewhat longitudinal slot 28 therein (see also Figure 5) which extends diametrically of the post at the bottom of the slot which is in the lower portion of bushing 22; the slot extends upwardly at an angle so that it emerges from the side of the post a distance slightly above the top of bushing 22. The arrangement is such that when bushing 24 is lifted to the broken line position against screw 25 the top of slot 26 is exposed, and the yarn or strand is then slipped into the slot, which extends diametrically of the post along a line between sleeve l 2 and snubbing device I0. Bushing 24 is then dropped down and it holds the strand in the slot. Bushings 22 and 24 have their ends somewhat rounded with the result that the strand passes the telescoping bushings with low resistance or frictional drag and without injury to the strand.

Directly below the bottom of slot 23 there is a shoulder 28 on post i8 and resting on this shoulder is a loose metal washer 30. The bottom wall of slot 26 is convex as shown so that it is high at the center of the post and extends downwardly at the sides toward washer 30. Thus, when the strand is at rest, bushing 24 is urged downwardly by gravity and pushes the strand against the washer as shown in Figure 8. When the bushing is so positioned, the strand is pressed against the convex bottom wall of the slot and at the two sides of the post the strand makes a rather sharp bend aganst the washer and around the bottom edges of bushing 24. This exerts a satisfactory holding effect upon the strand without there being a pinching action which would injure the strand, and yet the action is somewhat a light clamping of the strand so that there is no slipping. However, when the strand is drawn tight or starts to move the first action is to lift bu hing 24 to somewhat the position shown in Figure 3 wherein the bushing rides loosely on the yarn and there is no longer any clamping action.

As will be discussed below, when there is a tendency for harmonic oscillation to be set up between the tension device and the strand passing therethrough, the strand tends to flip bushing 24 up again=t screw 25, and when the bushing falls again it carries the strand with it downwardly against washer 39 with the result that the yarn is momentarily clamped as outlined above. This tends to stop the movement of the strand momentarily and throw the strand and tension device into discord so as to immediately dampen and stop the oscillation. However, the

clamping is substantially instantaneous so that it does not interfere with the proper delivery of the stran; and bushing 24 immediately moves back to the position shown in full lines so that the initial tension is maintained as discussed above.

As indicated above, the yarn passes from the primary tension device 8 to the snubbing device NJ and thence passes to the left through porcelain Sleeve [6 to the warper. The snubbing device.

is journalled in frame 2 and has a hub 31- which supports the rotor. Disc 34 has a downwardly directed peripherial flange 39 which overhangs a concentric rib 35 on the frame-. Equally f ce-cl around the periphery of these discs are synthetic sapphire rods, 4%, H, :32, 4-3, 44 and ends in the two discs thus to provide a squirrel arrangement, with disc 38 being supported by these rods.

Disc 38 (Fi ure 1) has a straight side 46 adcent rod and rod so projects above the top is of ing threading of the device. The bottom end'of this red projects below disc to and forms a stop (sigure 2) which is in alignment with. a stop i me 2 (so also Figure 8). Thus, the rotor may rotate from the position of Figure 6 counterclockwise through arc of approximately 336 to the position of Figure 8. The lower end of pivot shaft 35 projects through a bearing formed a boss 52 on frame 2, and coil d about this boss is a spring 5 One end 55 of spring 54 projects through an opening 5&5 in shaft 36 and the other end 5? projects through a slot 58 in the covering cup to. Cup- 68 is snugly received by a boss concentric with the boss 52 on fra is held in place by a retaining spring generally U shaped with a hump-65 at he center which engages the cup. One end dB or the spring is bent downwardly and outwardly as to be received in a recess 58 in a flange on the and the other end It is received in a hole '52 in a flange it at the edge of the frame. tension. on spring 54 may be changed by rotating cup on boss E2, and when the spring been adjusted the friction between boss 62 the cup is sufilcient to prevent the cup fromupon and clamps the strand as outlined above. To thread the snubbing device the operator holds the strand (see Figure 6 with one hand directly above rotor 32, and with the other hand engages the top of rod ii) and rotates the rotor clockwise against the action of spring 54 to Figure 6. The

strand is then lowered into the space between rod ii] the flat edge to of disc 38 and the rotor is released so that it is rotated counterclockwise by the spring to the position of Figure 8 wherein stop 48 engages stop 59.

This completes the threading operation and with the yarn at rest the elements assume the positions of Figure 8 with rotor 32 positioned so steps 38 and so are engaged and with bushing 2d clamping the strand lightly a ainst washer 39 and the bottom wall of slot 2-5. When the warp winding operation starts the initial action is to tighten up the strand at sleeve it but the slight clam-ping action of bushing 24 against washer 31? is sufficient to prevent the strand from sliding freely so that there is an immediate snub-hing of the strand on the rotor 32. The immediate efiect formed by a lowerdisc Rods ii to 4-5 are rigidly mounted at theirdisc 33 to aid in manipulating the rotor dur-- Spring has the complex shape shown,.

strand and rods 62] to Z5.

of thissnubbing is that the rotor starts to turn clockwise and a length of the strand is unwound so as to. permit the strand to start passing through sleeve I5. Simultaneously, however, the strand slides around the rotor and is tightened up between the snubbing device 19 and tension device 8 and this lifts bushing '24 away from Washer 30 with the result that the bushing then subjects the strand to only the slight resistance.

to movement which is incidental to passing the telescoped walls of the bushings 22 and 24.

For purposes of explanation of the snubbing action, reference should now be made to Figure 7 which is a somewhat schematic view wherein the axis of rotor 32 is shown as extending horizontally and the elements are positioned during operation when the strand is being drawn through the device. The incoming strand passes through sleeve 12 to the near top edge of bushing 22 and thence downwardly into recess 2| in the bushing where it passes through slot 25-6 in post, It! beneath bushing 24 and thence upwardly and out of the recess over the opposite top edge of bushing 22. From bushing 2|2 the strand passes to rod to and thence counterclockwise around this rod through a substantial angle, and then passes clockwise around the squirrel cage formed by rods 4! to 45 and leaves the device through sleeve 16.

The total or delivery tension of the strand at bushing I6 is maintained constant by virtue of snubbing device It producing .a variable tension which is compensated automatically to take care of variations in the tension of the strand passing to the snubbing device. The tension of the strand passing to the snubbing device is the sum ditions of ballooning of the strand. The ballooning varies greatly and the size of the cone formation from which the strand is withdrawn varies considerably.

As will be explained more fully below the tension produced by the primary tension device 8 varies to some extent to compensate for minor variations on the strand at sleeve I2 but even when the strand is moving at a constant rate the primary tension device cannot fully compensate for all variations in the tension at sleeve 12. In any event the variations in the tension produced by device 8 are small as compared with the variations in the tension produced by snubbing device 2e, and for purposes of the present discussion, the tension produced by device -8 may be considered substantially constant.

The tension produced by the snubbing device H3 varies over a wide range depending upon the angular position of the rotor. Assuming that the strand is being drawn through the device with a predetermined initial tension on the strand and that spring 54 is adjusted to a predetermined tension, the strand exerts a clockwise torque to the rotor because of the contact between the The amount of this torque is a function of the total angle of contact between the strand and the rods. Therefore, if the rotor turns clockwise from the position shown in Figure 7, thereby to decrease the angles of contact between theyam. and rods 48 and M,

the snubbing effect of device 10 is reduced; and, there is a continued reduction in the snubbing effect as the rotor continues to turn clockwise toward the position of Figure 6. Counterclockwise turning of the rotor from the position of Figure 7 toward the position of Figure 8 causes a corresponding increase in the snubbing effect.

In Figure '7 the elements are shown in an average angular position wherein the strand engages the various rods as follows: Rod 40, substantially 160; rod 4|, substantially 110; rods 42 and 43, substantially 60 each; rod 44, substantially 30; and rod 45 is not engaged. Thus when the rotor is positioned as indicated, the rods are engaged a total of approximately 360. When the rotor moves clockwise, this angle of engagement is reduced by virtue of decreasing the angular wrap of the strand around rods 40 and 44 and successively rods 43 and 42. When the rotor moves counterclockwise from the position shown in Figure 7, the angle of engagement with rods 40 and 44 is increased and then the strand engages rod 45. Upon further movement, the strand adjacent rod 40 engages rod 4| and thereafter the strand is wound further around the squirrel cage as the rotor approaches the position of Figure 8. The rods are of sufiicient length to permit the three runs of the strand to lie side by side without interference and the overhanging edges of discs 34 and 36 hold the strands on the squirrel cage.

As indicated above, the tension of spring 54 is adjusted by turning cup 60 and when once adjusted the spring exerts substantially constant torque throughout the turning movement of the rotor. Assuming that the spring is adjusted to exert a delivery tension of four grams, if the tension on the yarn passing through sleeve 16 is more than four grams the strand will turn the rotor clockwise so as to gradually reduce the angle of contact between the strand and the rods and thereby reestablish the four gram tension. The tension on the strand at sleeve [2 is negligibly low, and the tension produced by device 8 while the strand is passing through it is of a relatively low order. Therefore, with the four gram setting of the spring the withdrawing of the strand through sleeve I6 causes the rotor to assume such a position that it supplies a residual tension so that the tension on the strand at sleeve I6 is four grams. Then, as the tension at the supply or at device 8 changes, the rotor will instantaneously assume new positions to maintain the constant tension of the delivered strand.

When the warping operation is stopped, the break reaction tends to cause the strands to slacken considerably and in the past this has caused difficulties. With the present arrangement, when the warping operation is stopped, the snubbing device tends to maintain the constant tension and therefore turns counterclockwise from the position of Figure 7 to that of Figure 8. This winds up an appreciable amount of the strand and the action is instantaneous and automatic so that the strand tends to remain taut and this prevents any objectionable slack condition. The same action gives smooth performance if there is a sudden fluctuation or stoppage in the winding of the strand. Similarly, if during operation there is an instantaneous stoppage or jerking at the source of the strand, the rotor will turn clockwise so as to unwind a sufficient length of the strand to continue the operation without appreciable variation in the tension of the outgoing strand. Thus, in addition to maintaining constant tension, the snubbing device acts as a stabilizer where minor fluctuations in operating conditions are compensated for automatically and instantaneously by winding up or unwinding the strand.

As has been indicated above, the primary tension device produces a variable tension and the magnitude of the variations are sufficient to compensate for minor variations in the strand at sleeve l2. These variations in tension result from movement of the bushing 24 up and down within bushing 22. Thus, for example, considering the position of bushing 24 in Figure 7 as a normal operating position, an increase in tension at sleeve I2 causes the strand to move upwardly within recess 2| and lift bushing 24. This reduces the angles of contact between the strand and the edges of bushings 22 and 24 and therefore the tension produced by device 8 is decreased. A subsequent decrease in the strand tension at sleeve l2 causes bushing 24 to descend again and this increases the angles of contact so that greater tension is produced. The maximum tension condition is reached when the strand is stationary as in Figure 8 and bushing 24 and the strand rest on the washer In Figure 6 of the drawings the illustrative embodiment of the invention is shown substantially to scale whereas Figures 1 to 5 show the device enlarged to substantially twice normal size so as to bring out the details more accurately. In attaining certain objects of the invention, the dimensions are important although it is understood that under some circumstances the dimensions and the construction will b varied considerably.

As many possible embodiments may be made of the mechanical features of the above invention and as the art herein described might be varied in various parts, all without departing from the scope of the invention, it is to be understood that all matter hereinabove set forth, or shown in the accompanying drawings is to be interpreted as illustrative and not in a limiting sense.

I claim:

1. In a device for tensioning a strand, the combination of, a frame structure which is adapted to be rigidly supported by a creel or the like and an initial tension device which is adapted to have the strand from the supply pass therethrough and which imposes upon the strand an initial tension the magnitude of which is maximum when the strand is stationary and approaches a minimum value when the strand is moving at the normal expected rate, an automaticall varying snubbing device positioned to have the strand pass therethrough from said initial tension device and to impose upon the strand a variable snubbing effect, said snubbin device comprising a rotor formed by a pair of spaced parallel discs and a plurality of strand engaging elements mounted substantially between the peripheries of said discs and each presenting a convex surface to the strand, means pivotally mounting said rotor on the axis of said discs, a coil spring urging said rotor arcuately in such a direction as to tend to wind the incoming strand into the rotor, means to vary the tension of the spring, a cup enclosing the spring and having an opening through which one end of the spring extends, a boss integral with the pivotal means for said rotor which snugly receives the lip of the cup, and a substantially U-shaped spring member holding said cup in place, said snubbing device being so constructed and arranged that the are through which the strand is snubbed is varied in accordance with an inverse function of the tension on the strand passing to the snubbing device, whereby the strand passes from the tension device under constant tension.

2. In a device for tensioning a strand, the comination of, a frame structure which is adapted to be rigidly supported by a creel or the like and an initial tension device which is adapted to have the strand from the supply pass therethrough and which imposes upon the strand an initial tension the magnitude of which is maximum when the strand is stationary and approaches a minimum value when the strand is moving at the normal expected rate, said initial tension device comprising a pair of telescoping porcelain bushings having a satin finish surface and positioned concentri ally with one bushing being adapted to move to and from a maximum tension position wherein one of its ends is telescoped within one end of the other bushings and mounting means for said bushings including a stationary post extending through said bushings and holding said bushings in alignment and means to limit the relative axial movement of said bushings, and an automatically varying snubbing device positioned to have the strand pass therethrough from said initial tension device and to impose upon the strand a variable snubbing efiect, said snubbing device being so constructed and arranged that the are through which the strand is snubbed is varied in accordance with an inverse function of the tension on the strand passing to the snubbing device, whereby the strand passes from the tension device under constant tension.

3. A device as claimed in claim 1 wherein one of said strand engaging elements has the strand engaging it through an arc of substantially 180 or more and the remainder of said elements is engaged by the strand through an are substantially 60 or less.

4. In a device for tensioning a strand, the combination of, a fixed member including a wall structure so constructed and arranged that a strand may pass successively two Wall portions with a recess therebetween, means to divert the strand from one wall portion into said recess and thence to the other wall portion including a movable member which has an end portion which is urged against the strand and into said recess, said wall structure and said movable member are two porcelain bushings of such size that they telescope at their ends with the end of one being adapted to enter the recess in the other, a stationary post concentrically positioned within said porcelain bushings and having a substantially diametrically extending slot through which the strand extends thereby to hold the strand in diametric relationship with respect to the bushmgs.

5. A device as described in claim 4 which includes, a washer mounted on said post within the said recess and adapted to provide an abutment limiting the entry of the movable bushing into said recess.

6. A device as claimed in claim 5 which includes, a screw carried by said post at the end, opposite said washer and having a head portion which overhangs the edge of the post thereby to hold the movable bushing on the post.

7. A device as described in claim 6 which in-' cludes, a frame structure upon which said wall construction and said post are rigidly mounted, and a snubbing device mounted on said frame structure and adapted to have the strand pass through it.

8. A snubbing device for a strand comprising, a pivot structure, an automatically varying snubbing rotor mounted on said pivot structure and adapted to rotate about an axis and to exert an automatically varying snubbing eiTect upon the strand depending upon the position of said rotor, biasing means urging said rotor about said axis, and means to exert an initial tension on a strand passing to said structure comprising a wall structure forming a recess, and means for clamping the strand lightly when the strand is stationary but so arranged as to exert no clamping action when the strand is moving.

9. A snubbing device for a strand comprising, a rotor having two parallel discs positioned in spaced relationship and having a common axis and a plurality of sapphire rods equally spaced around the peripheries of said discs thereby forming a squirrel cage arrangement, one of said rods having an opening between itself and one of said discs, and means urging said rotor about said axis.

10. In a snubbing device for a strand the combination of, a rotor including a pair of spaced parallel disc members and a plurality of contact rods positioned substantially evenly around the periphery of said disc members with the other of said disc members being rigidly carried by said rods, one of said rods projecting at its two ends beyond the disc members and being free of said other disc members, and pivot means for said rotor.

11. In a device of the character described, the combination of, a fixed post having a substantial diametrical opening therethrough for a strand, a loose washer mounted on said post substantially at the bottom of said opening, a fixed bushing concentrically positioned around said post throughout the zone of said washer and providing an annular recess around said post, a

FREDERICK J. KENT.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 67,519 Fewkes Aug. 6, 1867 399,872 Gibbs Mar. 19, 1889 1,744,760 Grondahl Jan. 28, 1930 1,762,049 Clinton June 3, 1930 2,128,033 Zonis Aug. 23, 1938 2,393,995 Lambach et al Feb. 5, 1946 FOREIGN PATENTS Number Country Date 64,127 Sweden June 11, 1926 

